Electric safety-switch.



67,@ ONM D. PLATT'.

ELECTRIC SAFETY SWITCH.

APPLICATION FILED HAR. 22, 1910.

Patented Aug. 30, 1910.

UNITED sTATEs PATENT our-ion.K

CLARENCE i). BLATT, or BRIDGEPCRT, CONNECTICUT.

Specication of Letters Patent. application-mea March 22,1910. semi No.

ELECTRIC SAFETY-SWITCH.

Patented Aug.

Toall whom 'it may concern:

- Be it known that I, CLARENCE D.- PLATT. a citizen of the United States, residing at Bridgeport, county of Fairfield, State of Connecticut, have invented an Improvement in Electric Safety-Switches, of which the following is a specification.

Thisinvention has for its object to provide a safetyswitch of the double break knifel type, which shall be so constructed that the operative parts may be immersed in oil or any arc preventing fluid and which shall furthermore be so constructed as to make the switch safe under ordinary condi/- tions even though the operative parts should not be immersed in an 'are preventing fluid. A further object of the invention is to produce va quick acting double break switch :which shall be strong and durable and able to stand the hardest kind of service and which shall be so simple in construction and iirexpensive to produce as to enable its use in many cases in which this class of switches has not heretofore-.been used on account of their'prohibitive cost which Ahas prevented their use except where absolutely required` by the'conditions.

A further object of the invention is to produce a vswitch which by reason of im- ,portant improvements in the details of construction shall be especially adapted for use in mines, cotton mills, powder mills and l various places where dangerous latmospheric conditions exist and where a flash might produce a serious accident, said details of construction furthermore greatly prolongp ing the life of the switc A further object ofthe invention is to produce a switch in which the operative parts shall be mounted upon a detachable frame which may be removed Without disturbing the casing, the terminals being readily accessible without removing the switch from the casing and the casing adapted to be filled without disturbing either switch or casing.

With the above and other objects in view I have devised the novel safety switch which I `will now describe referring to the accompanying drawing forming specification and usingre erence Characters to indicate the several arts:

Figure l is a front e evation of my novel switch as in use, partly broken, away to show the operative parts; Fig. 2 an end elevation as seen from the right in Fig. 1,

Fig. 4 a front elevation with oil or emptied a part of this` partly in vertical section; Fig. 3 a plan view of the capremoved and. partly broken away; of the switch incchanism removed and partly broken away; Fig. 5 an end elevation as seen from the right in Fig. 4, partly in vertical section; Fig. 6 an inverted plan view of the blade carrying block detached; Fig. 7 a plan view of the' 'base block detached; and Fig. 8 an linvert-ed plan view of the base block showing the wiring.

I have illustrated the invention asapplied to a double pole switch. It should be understood, however, that the` principle is equally applicable to single, triple or other multiple pole switches, a blade and pair of contact plates being addedV for each wire.

10 denotes the casing which is cast in a single piece and is provided with lugs 11 having screw holes for tachment in'place, which is secured to the purpose of atand 12 denotes the cap the casing by screws 13.

The switch mechanism is mounted on a U- shaped frame 14 which is inclosed within the casing and the cap.

15 denotes the shaft which is mounted in the frame and passes through the terminal block 16 which 1s also secured to the frame. The casing and the cap are provided with vcorresponding half sockets 17 which form bearings for the shaft, thus permitting the frame and the entire switch mechanism to be lifted out of the casing upon the removal of the cap and the screws 46 whichsecure the frame rigidly to the casing.

18 denotes a base block which is secured to the frame and is provided with recesses 19 in which t-he contact plates or jaws 2O are secured, the Contact of the inverted U-type. 2l denotes guide pins which ai'erigldly secured in the base block and extend upward therefrom.

22 denotes the contact blades which arc molded into 'a switch block 28 adapted to slide on the guide pins. 'I he switch block and contact blades are forced away from the base and the contact plates by means of a spring 24 which is recessed into the base block and the switch block. The switch block is connected to the shaft by means of a link 25 one end of which is pivoted to a bracket 26 on the switch block, the other end being ivoted to a crank 27 upon the shaft. In or er that the movement of the switch may be relatively hard in closing the circuit plates shown bei u g and relatively easy in openingthe circuit, I have constructed and arranged the parts so that the crank will lie in substantially the horizontal plane when the switch is open and have located the bracket on the upper side of .the switch block off center on the side of the crank. An operating leverBO which is secured to the shaft and swings over the outer face of the casing is stopped at the opposite extremes of its movement by means of lugs 28 and 29 on the casing. Lug 28 being marked Off, which indicates that the current is off, z'. e., that the circuit is open, and lug 29 being marked On, which indicates that the current is on, d. e., that the circuit is closed. a

To close the circuit the operator swingsl the lever from the position shown in Fig. 1 to the position shown in Fig. 4. As the lever is moved from the position in Fig. 1

the spring is compressed, the crank and link being so arranged that their pivotal point "which is indicated by 31 will swing slightly past the center, as shown in Fig. 4, and the spring will then act Bto retain Vthe switch block and contact blades in the circuit clos- 4 ing position. 'Ihat is, the spring will act to hold the operating lever in engagement with stop 29.' To open the circuit, the lever is swung Vtoward the right from the position shown in Fig. 4. As soon as pivotal point 31 of the link to the crank has passed the center, the spring will act to raise the switch block and blades, thus making an easy and quick opening movement.

32 denotes the line conductors and 33 the load conductors. These conductors pass through holes 47 in an linsulating block 34 which is secured in the cover. An extension of this block, indicated by 35, passes through van opening' 36 in the cover. I thus avoid the possibility 'of any contact of the conductors with the cover. Fronrlblock 34 the conductors proceed to terminal block 16- the switch are thoroughly insulated so that danger of short circuiting iseliminated..

'I e casing may be readily illed with oil by removing othe cover. As a simple means of draining the casing should it be required to change the oil, I provide-a hub' 42 at the lower end of the casingV having a hole 43 vleading into the casing, said lhole being closed by means of a screw 44, a packing washer or washers 45 being preferably placed under the head of the screw.

Having thus described my invention, I claim 1. In a switch of the character described, the combination with a casing and cap therefor, each provided with half sockets, of a U-shaped frame removably mounted in said casing, switch mechanism supported by'said frame, and an operating shaft journaled in the said .half sockets.

2. In a switch of the character described,

the combination with a casing and cap each provided with half sockets, of a removable frame within the casing, a base block secured thereto and carrying contact plates, a terminal block also secured to the frame, electrical connections between said blocks, a sliding switch block carrying contact blades, an operating shaft journaled in the half sockets and operating connections between said shaft and the switch block.

3. In a switch of the character described, the combination with a casing and cap, of a removable frame, a base block secured thereto and carrying contact plates, a terminal block also secured to the frame, electrical.,connections between said blocks, a sliding switch block carrying contact blades, an operating shaft and connections between said shaft and the switch"b"lock.'-

4. In a switch of the character described, the combination with a casing and cap, a removable frame secured to the casing, base and terminal blocks secured to 'the frame, contact plates secured to the base block and electrical connections between said blocks, of a sliding switch block carrying contact blades, an operating shaft and connections between said shaft and the switch block.-

5. In a switch of the character described,

removable frame secured to the casing, base and terminal blocks secured to the frame, contact plates `secured to the base block and electrical connections between said blocks, of a sliding switch'block carrying contact blades, an operating shaft having a crank and a link connecting said crank with the switch block.

6. In a switch of the character described, the combination with a casing and cap, a removable frame secured to the casing, base and terminal blocks secured to theframe, contact plates secured to the base block and electrical connections between said blocks, of a sliding switch block carrying contact blades, and a .bracket on its upper side placed off-center, an operating shaft having a crank on the side corresponding with the bracket in the open position and a link connecting the crank and the bracket.

7. In a switch of the character described, the combination with a casing and cap, a

the combination with a casing and cap, a

removable frame secured to the casing, base and terminal blocks secured to the frame, contact plates secured to the 'base block and electrical connections between said blocks, of a sliding switch block carrying contact blades, a spring socketed in the base and switch block and acting` to raise the switch block, an operating shaft having a crank and a link connecting said crank and the switch block and acting to close the switch against the power of the spring.

8. In a switch of the character described, the combination with a casing and cap, a removable frame secured to the casing, an insulating base block secured to the frame and provided with recesses, and pairs of Contact plates in said` recesses, of a terminal block, electrical connections between the terminal block and the Contact springs, a sliding switch block carrying contact blades, an operating shaft having a crank anda link connecting said crank with the switch block.

9. In a switch of the character described, the combination with a casing and ca a removable frame secured to the casing, an insulating base block secured to the frame and carrying contact plates, and guide pins extending from the base block, of an 1nsulating switch block adapted to slide on the guide pins and carrying contact blades, a spring acting to raise the switch block, an operating shaft having a crank and a link connecting' the crank with the switch block and acting to close the switch against the powerof the spring.

In testimony whereof I aiX my signature in presence of two Witnesses.

CLARENCE D. PLATT.

Witnesses A. M. VVoos'rER, S. W. ATHERTON. 

